A semiconductor device includes first and second stacked semiconductor dies on a substrate. The outer ring assembly comprises an outer ring rotatably coupled to the inner ring, and a plurality of rolling elements that resides between the inner ring and the outer ring. The frame-based inferences may be supplemented by a rules-based inference system. Furthermore, the transparent smart light source can serve as a curtain blocking out external light, as well as a lighting device, and also can be combined with a solar cell to generate electric power.